TY - JOUR
T1 - Adsorption of As(V) and As(III) by nanocrystalline titanium dioxide
AU - Pena, Maria E.
AU - Korfiatis, George P.
AU - Patel, Manish
AU - Lippincott, Lee
AU - Meng, Xiaoguang
PY - 2005/6
Y1 - 2005/6
N2 - This study evaluated the effectiveness of nanocrystalline titanium dioxide (TiO2) in removing arsenate [As(V)] and arsenite [As(III)] and in photocatalytic oxidation of As(III). Batch adsorption and oxidation experiments were conducted with TiO2 suspensions prepared in a 0.04 M NaCl solution and in a challenge water containing the competing anions phosphate, silicate, and carbonate. The removal of As(V) and As(III) reached equilibrium within 4 h and the adsorption kinetics were described by a pseudo-second-order equation. The TiO2 was effective for As(V) removal at pH<8 and showed a maximum removal for As(III) at pH of about 7.5 in the challenge water. The adsorption capacity of the TiO2 for As(V) and As(III) was much higher than fumed TiO2 (Degussa P25) and granular ferric oxide. More than 0.5 mmol/g of As(V) and As(III) was adsorbed by the TiO2 at an equilibrium arsenic concentration of 0.6 mM. The presence of the competing anions had a moderate effect on the adsorption capacities of the TiO2 for As(III) and As(V) in a neutral pH range. In the presence of sunlight and dissolved oxygen, As(III) (26.7 μM or 2 mg/L) was completely converted to As(V) in a 0.2 g/L TiO2 suspension through photocatalytic oxidation within 25 min. The nanocrystalline TiO2 is an effective adsorbent for As(V) and As(III) and an efficient photocatalyst.
AB - This study evaluated the effectiveness of nanocrystalline titanium dioxide (TiO2) in removing arsenate [As(V)] and arsenite [As(III)] and in photocatalytic oxidation of As(III). Batch adsorption and oxidation experiments were conducted with TiO2 suspensions prepared in a 0.04 M NaCl solution and in a challenge water containing the competing anions phosphate, silicate, and carbonate. The removal of As(V) and As(III) reached equilibrium within 4 h and the adsorption kinetics were described by a pseudo-second-order equation. The TiO2 was effective for As(V) removal at pH<8 and showed a maximum removal for As(III) at pH of about 7.5 in the challenge water. The adsorption capacity of the TiO2 for As(V) and As(III) was much higher than fumed TiO2 (Degussa P25) and granular ferric oxide. More than 0.5 mmol/g of As(V) and As(III) was adsorbed by the TiO2 at an equilibrium arsenic concentration of 0.6 mM. The presence of the competing anions had a moderate effect on the adsorption capacities of the TiO2 for As(III) and As(V) in a neutral pH range. In the presence of sunlight and dissolved oxygen, As(III) (26.7 μM or 2 mg/L) was completely converted to As(V) in a 0.2 g/L TiO2 suspension through photocatalytic oxidation within 25 min. The nanocrystalline TiO2 is an effective adsorbent for As(V) and As(III) and an efficient photocatalyst.
KW - Adsorption
KW - Arsenic speciation
KW - Challenge water
KW - Photocatalytic oxidation
KW - TiO
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U2 - 10.1016/j.watres.2005.04.006
DO - 10.1016/j.watres.2005.04.006
M3 - Article
C2 - 15896821
AN - SCOPUS:20544452256
SN - 0043-1354
VL - 39
SP - 2327
EP - 2337
JO - Water Research
JF - Water Research
IS - 11
ER -